December 2021, Volume 71, Issue 12

IMAGING CORNER

Incidental COVID-19 pneumonia on oncologic 18F-FDG PET-CT scan in asymptomatic patient

Tanzil Sajad  ( Department of Nuclear Medicine, Shaukat Khanum Memorial Cancer Hospital and Research Centre, Lahore, Pakistan. )
Aamna Hassan  ( Department of Nuclear Medicine, Shaukat Khanum Memorial Cancer Hospital and Research Centre, Lahore, Pakistan )

Abstract

Corona virus disease 2019 (COVID-19), originated from Wuhan province of China, is responsible for causing severe respiratory syndrome (SARS-Cov-2). Initial specific investigation to diagnose the viral infection includes nasopharyngeal nucleic acid testing (RT-PCR). However other modalities can also aid in detection of COVID-19 infection. For instance, COVID pneumonitis related findings on positron emission tomography (PET/CT) scan acquired, during routine evaluation; can help in detection the viral infection in asymptomatic patients thereby preventing further spread of infection to other patients, physicians; and family members. This can alert physicians in taking prophylactic and preventive measures for management of these asymptomatic patient.

 

Keywords: Asymptomatic COVID pneumonia, 18F FDG PET-CT, Incidental FDG uptake.

 

A 36 years old man with excisional biopsy proven diagnosis of diffuse large B-Cell lymphoma (DLBCL) underwent interim PET/CT scan after three cycles of chemotherapy. PET/CT scan was performed after intravenous injection of 370MBq of Fluorodeoxyglucose (FDG). Axial and coronal views of the scan (Figure-A & B) showed bilateral diffuse air space changes and resolving consolidations showing increased FDG uptake. On inquiring, patient reported no signs and symptoms related to COVID pneumonia. COVID PCR of the patient confirmed the presence of COVID infection. After recommended period of COVID infection isolation and remaining cycles of chemotherapy were given accordingly and patient remained asymptomatic during this whole period.

COVID-19 virus primarily involves the lungs, however, it can spread in extra pulmonary sites as well; including bowel, liver, brain, kidneys, cardiovascular system, and cerebrovascular system.1 Conventional imaging including computed tomography has low specificity in assessing infectious and inflammatory diseases. 18FFDG PET-CT scanning can be utilized to evaluate COVID infection involving not only the lungs but the entire human body and has been found to have a higher specificity than other conventional imaging modalities.1  Several asymptomatic cases of COVID-19 infection have been documented in oncological patients during routine PET-CT imaging.2  In COVID infection metabolic changes can precede and be more significantly worse than morphological changes; therefore, PET can be used as an early predictor of inflammation as well as cancer.3

References

 

1. Alavi A, Werner TJ, Gholamrezanezhad A. The critical role of FDG-PET/CT imaging in assessing systemic manifestations of COVID-19 infection. Eur J Nucl Med Mol Imaging. 2021; 48:956-962.

2. Colandrea M, Gilardi L, Travaini LL, Fracassi SLV, Funicelli L, Grana CM. 18F-FDG PET/CT in asymptomatic patients with COVID-19: the submerged iceberg surfaces. Jpn J Radiol. 2020; 38:1007-1011.

3. Minamimoto R, Hotta M, Ishikane M, Inagaki T. FDG-PET/CT images of COVID-19: a comprehensive review. Glob Health Med. 2020; 2:221-226.

Journal of the Pakistan Medical Association has agreed to receive and publish manuscripts in accordance with the principles of the following committees: